Our overall objective is to determine the extent to which light scattering measurements can be used as a tool to probe structures in normal and abnormal corneas. This is to be accomplished by quantitating light scattering through careful experimental measurements, complemented by theoretical analyses based on the structural features determined from electron microscopy (EM), from structure models, or from both. Comparisons test the validity of the structural models, or of the EM, and permit us to relate the cornea's structure to its scattering properties. Indeed we have shown that light scattering can be used to decide among the various models that have been proposed to explain corneal transparency and its loss with swelling. Recently, we have demonstrated that information about lamellar orientations can be obtained from the scattering of polarized light; and that the lammella waviness, whch is present whenever the fibril tension is significantly reduced, causes the observed small-angle light scattering patterns. These findings have important ramifications regarding the mechanical properties of the cornea, which are the foundation for understanding corneal curvature and corneal behavior during surgical procedures. Our specific aims regarding the collagen fibril arrangement are: to develop techniques to calculate scattering from generally inhomogeneous spatial distributions of fibrils having an arbitrary distribution of diameters; and to apply variational techniques to account for possible multiple scattering effects. These studies apply to cold swollen corneas, to scar tissue, and to other abnormal corneas. Our specific goals concerning lamellar structures are: improved calculations of propagation and scattering in anisotropic layered media (corneal lamellae); extended measurements of corneal birefringence effects; and EM to characterize familiar orientations and to investigate the conditions leading to the formation of voids (lakes) in cold swollen corneas. These studies are essential for understanding the structural implications of birefringence and for understanding birefringence effects on small angle light scattering. Finally, we will extend our experiments to include human corneas.